Chicken, quail catch and shed high volumes of new H7N9 flu, study shows

[Shiloh]

Source: http://www.mysask.com/portal/site/m...x.portlet.endCacheTok=com.vignette.cachetoken


Chicken, quail catch and shed high volumes of new H7N9 flu, study shows
Helen Branswell, The Canadian Press
Wed, 5 Jun 2013 16:02:00 CST


Chickens and quail are highly susceptible to the new H7N9 bird flu, and shed high volumes of virus when they are infected, new research reveals.

The work, which hasn't yet been published, suggests these two types of birds may be key to the explosive outbreak of the new flu that erupted in China earlier this spring.

The research, done at the U.S. Department of Agriculture's Southeast Poultry Research Laboratory in Athens, Ga., also found something interesting about the way this virus acts in poultry.

In birds, influenza is an infection of the gut, not the respiratory tract. And when chickens or ducks or other infected birds shed flu viruses, it is normally via the cloaca, the anus. But the chickens and quails infected at the Athens laboratory shed H7N9 virus from their nasal passages. That suggests if people testing birds for the virus only swabbed cloacal passages, they might not find evidence of infection...

 

[AnnaLisa]

Re: Chicken, quail catch and shed high volumes of new H7N9 flu, study shows

Very interesting.

 

[gsgs]

Re: Chicken, quail catch and shed high volumes of new H7N9 flu, study shows

Is it really "birds" or only ducks,mallards (not chickens) where flu usually infects in the intestine ?
What was with the ancestral H9N2 in East China chickens since the 90s, also GI ?


-----------edit---------------

OK, I searched a bit and found this:

http://openi.nlm.nih.gov/detailedresult.php?img=3114738_1297-9716-42-64-1&req=4

trachea,lungs and intestines were equally infected in chickens with
A/Chicken/Korea/S21/2004 (H9N2) [21,9,21,-,11,-,8,27]
---well, this H9N2 is quite different from the one in Shanghai, I better search for a better match---

--------------------found this:-------------
http://pinnacle.allenpress.com/doi/abs/10.1637/8937-052809-Reg.1?journalCode=avdi

> In conclusion, A/Chicken/Shanghai/F/1998(H9N2) [close to the ancestor of H7N9 in segments 2,3,5,8]
> acquired [between 1994 and 1998] the ability of airborne transmission and replicated with a
> higher efficiency in the respiratory tract of the chickens.

this was achieved (presumably) mainly by changes in HA,NA

-----------------------found this:---------------
http://jvi.asm.org/content/83/17/8428.full.pdf

Most of the H9N2 viruses were shed mainly
from the respiratory tract with titers in the range of 4.0 to 7.0
log10EID50/0.1 ml in tracheal swabs on day 5 postinfection
(p.i.). The maximal virus shedding was observed between the
3rd and 5th day postinoculation. Viruses were detected in
tracheal swabs of the contact birds from day 3 postcontact.
Virus was mostly detected in the cloacal swabs of directly
inoculated birds on day 3 p.i. Lower virus titers were detected
in the cloacal swabs than in the tracheal swabs from both
inoculated and contact birds. It is notable that biological dif-
ferences in H9N2 viruses of different genotypes were obvious.
For example, most genotype A viruses replicated mainly in
inoculated chickens but failed to be transmitted efficiently to
the aerosol contact group. In contrast, most genotype H and
genotype K viruses from 2001 onwards not only replicated
efficiently in infected chickens but also were transmitted effi-
ciently among aerosol contact chickens (Fig. 5; see also Table
S2 in the supplemental material).